Samsung has finished developing an internal test version of Android 4.1 for the Galaxy S III, and is now working on a public release version of the software, according to SamMobile. This means that Jelly Bean will be coming to Samsung's flagship phone after the release version is polished and approved by Google. SamMobile estimates that it will launch around the end of Q3 or beginning of Q4, but that timeline has not been confirmed by Samsung.
SamMobile also reports that Samsung is still testing Android 4.1 updates for the Galaxy S II and the Galaxy Note, and has not found a reason not to update either device. As for the Galaxy Note II — widely expected to be announced at IFA later this month — the site says that the device's test software is currently based on Android 4.0, but that may change before the product's launch. If the Galaxy Note II does not launch with Jelly Bean, it will likely be updated within a few months of release.